Partially merge #17650

Merges 647eb2cf1cd65b0391e3584361f0fc76246e64f3. The pull request as a
whole is quite large, and I'm reviewing the smaller pieces individually.

3 files changed, 20 insertions, 147 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb b/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
deleted file mode 100644
index 1b74c039ce..0000000000
--- a/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
+++ /dev/null
@@ -1,93 +0,0 @@
-module ActiveRecord
-  module ConnectionAdapters
-    module PostgreSQL
-      module ArrayParser # :nodoc:
-
-        DOUBLE_QUOTE = '"'
-        BACKSLASH = "\\"
-        COMMA = ','
-        BRACKET_OPEN = '{'
-        BRACKET_CLOSE = '}'
-
-        def parse_pg_array(string) # :nodoc:
-          local_index = 0
-          array = []
-          while(local_index < string.length)
-            case string[local_index]
-            when BRACKET_OPEN
-              local_index,array = parse_array_contents(array, string, local_index + 1)
-            when BRACKET_CLOSE
-              return array
-            end
-            local_index += 1
-          end
-
-          array
-        end
-
-        private
-
-          def parse_array_contents(array, string, index)
-            is_escaping  = false
-            is_quoted    = false
-            was_quoted   = false
-            current_item = ''
-
-            local_index = index
-            while local_index
-              token = string[local_index]
-              if is_escaping
-                current_item << token
-                is_escaping = false
-              else
-                if is_quoted
-                  case token
-                  when DOUBLE_QUOTE
-                    is_quoted = false
-                    was_quoted = true
-                  when BACKSLASH
-                    is_escaping = true
-                  else
-                    current_item << token
-                  end
-                else
-                  case token
-                  when BACKSLASH
-                    is_escaping = true
-                  when COMMA
-                    add_item_to_array(array, current_item, was_quoted)
-                    current_item = ''
-                    was_quoted = false
-                  when DOUBLE_QUOTE
-                    is_quoted = true
-                  when BRACKET_OPEN
-                    internal_items = []
-                    local_index,internal_items = parse_array_contents(internal_items, string, local_index + 1)
-                    array.push(internal_items)
-                  when BRACKET_CLOSE
-                    add_item_to_array(array, current_item, was_quoted)
-                    return local_index,array
-                  else
-                    current_item << token
-                  end
-                end
-              end
-
-              local_index += 1
-            end
-            return local_index,array
-          end
-
-          def add_item_to_array(array, current_item, quoted)
-            return if !quoted && current_item.length == 0
-
-            if !quoted && current_item == 'NULL'
-              array.push nil
-            else
-              array.push current_item
-            end
-          end
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
index f486c5ecb7..3de794f797 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -5,29 +5,20 @@ module ActiveRecord
         class Array < Type::Value # :nodoc:
           include Type::Helpers::Mutable
 
-          # Loads pg_array_parser if available. String parsing can be
-          # performed quicker by a native extension, which will not create
-          # a large amount of Ruby objects that will need to be garbage
-          # collected. pg_array_parser has a C and Java extension
-          begin
-            require 'pg_array_parser'
-            include PgArrayParser
-          rescue LoadError
-            require 'active_record/connection_adapters/postgresql/array_parser'
-            include PostgreSQL::ArrayParser
-          end
-
           attr_reader :subtype, :delimiter
           delegate :type, :user_input_in_time_zone, :limit, to: :subtype
 
           def initialize(subtype, delimiter = ',')
             @subtype = subtype
             @delimiter = delimiter
+
+            @pg_encoder = PG::TextEncoder::Array.new name: "#{type}[]", delimiter: delimiter
+            @pg_decoder = PG::TextDecoder::Array.new name: "#{type}[]", delimiter: delimiter
           end
 
           def deserialize(value)
             if value.is_a?(::String)
-              type_cast_array(parse_pg_array(value), :deserialize)
+              type_cast_array(@pg_decoder.decode(value), :deserialize)
             else
               super
             end
@@ -35,14 +26,14 @@ module ActiveRecord
 
           def cast(value)
             if value.is_a?(::String)
-              value = parse_pg_array(value)
+              value = @pg_decoder.decode(value)
             end
             type_cast_array(value, :cast)
           end
 
           def serialize(value)
             if value.is_a?(::Array)
-              cast_value_for_database(value)
+              @pg_encoder.encode(type_cast_array(value, :serialize))
             else
               super
             end
@@ -63,41 +54,6 @@ module ActiveRecord
               @subtype.public_send(method, value)
             end
           end
-
-          def cast_value_for_database(value)
-            if value.is_a?(::Array)
-              casted_values = value.map { |item| cast_value_for_database(item) }
-              "{#{casted_values.join(delimiter)}}"
-            else
-              quote_and_escape(subtype.serialize(value))
-            end
-          end
-
-          ARRAY_ESCAPE = "\\" * 2 * 2 # escape the backslash twice for PG arrays
-
-          def quote_and_escape(value)
-            case value
-            when ::String
-              if string_requires_quoting?(value)
-                value = value.gsub(/\\/, ARRAY_ESCAPE)
-                value.gsub!(/"/,"\\\"")
-                %("#{value}")
-              else
-                value
-              end
-            when nil then "NULL"
-            else value
-            end
-          end
-
-          # See http://www.postgresql.org/docs/9.2/static/arrays.html#ARRAYS-IO
-          # for a list of all cases in which strings will be quoted.
-          def string_requires_quoting?(string)
-            string.empty? ||
-              string == "NULL" ||
-              string =~ /[\{\}"\\\s]/ ||
-              string.include?(delimiter)
-          end
         end
       end
     end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 37bf4d77f8..e616cee5eb 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -1,3 +1,7 @@
+# Make sure we're using pg high enough for type casts and Ruby 2.2+ compatibility
+gem 'pg', '~> 0.18'
+require 'pg'
+
 require "active_record/connection_adapters/abstract_adapter"
 require "active_record/connection_adapters/postgresql/column"
 require "active_record/connection_adapters/postgresql/database_statements"
@@ -12,10 +16,6 @@ require "active_record/connection_adapters/statement_pool"
 
 require 'arel/visitors/bind_visitor'
 
-# Make sure we're using pg high enough for Ruby 2.2+ compatibility
-gem 'pg', '~> 0.18'
-require 'pg'
-
 require 'ipaddr'
 
 module ActiveRecord
@@ -278,6 +278,7 @@ module ActiveRecord
         @table_alias_length = nil
 
         connect
+        add_pg_encoders
         @statements = StatementPool.new @connection,
                                         self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 })
 
@@ -803,6 +804,15 @@ module ActiveRecord
           end
         end
 
+        def add_pg_encoders
+          map = PG::TypeMapByClass.new
+          map[Integer] = PG::TextEncoder::Integer.new
+          map[TrueClass] = PG::TextEncoder::Boolean.new
+          map[FalseClass] = PG::TextEncoder::Boolean.new
+          map[Float] = PG::TextEncoder::Float.new
+          @connection.type_map_for_queries = map
+        end
+
         def add_pg_decoders
           coders_by_name = {
             'int2' => PG::TextDecoder::Integer,